EMPLOYEE BENEFIT PLANS - Schedule of weighted average assumptions used in determining benefit obligations (Details)	Sep. 30, 2021	Sep. 30, 2020
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Weighted average discount rate	2.58%	2.30%
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Weighted average discount rate	1.94%	1.69%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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